<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
		<script type="text/javascript">
		
			function fun() {
				return; // 相当于返回undefined, 如果函数中不写return, 则也会返回undefined
			}

		</script>
	</head>
	<body>
	</body>
</html>
